Such pumps have various advantages. They are dry running safe and self-inducing. Also brief overloading thereof is not critical. No shaft seals and no rotating members in the product flow are required. Furthermore, the pump is not sensitive with respect to solids. Contaminants and solid materials can be conveyed in the product flow. Furthermore, displacement pumping of such a pump can be used also for shear-sensitive media. However, it is a drawback that, in particular at high pump pressures such as up to 6 bar, substantial compression power has to be available due to the compressibility of the air. This is why such diaphragm pumps are not economical at higher pressures.
From the brochure "Membranpumpen Typ Wiking M" of the firm Abel GmbH & Co. Pumpen- und Maschinenbau it becomes known to operate the diaphragm mechanically. A piston rod is connected to a yoke which is pivotally mounted to a link rod. However, the mechanical expenditure of such a pump is substantial. Furthermore, a single diaphragm pump generates strong pulsations and pumps only 50% of the pump rate of a double diaphragm pump at the same speed of the drives.
The problem to be solved by the invention is to provide a double diaphragm pump which is of simple structure and operates safely and which can be powered at high efficiency even at high pump pressures.